Methods of and apparatus for cutting strip material



R. F. HERR METHODS OF AND APPARATUS FOR CUTTING STRIP MATERIAL FiledMarch 28, 1957 4 Sheets-Sheet l INVENTOR. RICHARD E HERR ATTORNEY R. F.HERR Jan. 8, 1.963

METHODS OF AND APPARATUS FOR CUTTING STRIP MATERIAL 4 Sheets-Sheet 2Filed March 28, 1957 INVEN TOR. RICHARD F HERR Arronusv Jan. 8, 1963 R3,072,001

METHODS OF AND APPARATUS FOR CUTTING STRIP MATERIAL Filed March 28, 19574 Sheets-Sheet 5 IE1 INVENTOR.

' RICHARD F HERR Q Q ATTORNEY an. 1963 R. F. HERR 3,072,001

METHODS OF AND APPARATUS FOR CUTTING STRIP MATERIAL Filed March 28, 19574 Sheets-Sheet 4 INVEN TOR. RICHARD F HERR United rates Fatent Q a3,072,0ll1 METHODS OF AND AIIARATUS FGR CUTTING STRIP MATERIAL RichardF. Herr, (Icrtiand, ()hio, assignor to The Herr Equipment CorporationFiled Mar. 28, 1957, ser. No. 649,222 1 Claim. (El. 83-147) The presentinvention relates to material cutting, more particularly to methods ofand apparatus for severing strip material to form transformerlaminations, and the principal object of my invention is to provide newand improved methods and apparatus of the character described. Thisapplication is a continuation-in-part of my co-pending applicationSerial Number 431,551, filed May 21, 1954, and issued June 3, 1958, asLetters Patent 2,837,159.

In cutting laminations for use in building large electricaltransformers, several diflicult problems are presented. One of theproblems is due to the fact that the abuttin edges of respectiveadjoining laminations must fit together as nearly perfect as possible inorder to provide an efficient, quiet transformer. It will be appreciatedthat cutting the laminations from relatively thin strip with therequisite degree of accuracy, particularly when each lamination may beof considerable length, is extremely difiicult.

Moreover, the strip material from which the laminations are cut is veryexpensive since it is made by a special process to provide certainmagnetic properties. Accordingly, when cutting transformer laminations,scrap must be held to an absolute minimum since such scrap results inlosses which are quite high in view of the large tonnages of laminationswhich are cut.

One of the prior art solutions to the problem of minimizing scrap,particularly when cutting keystone shaped laminations, is mounting oneor more of the cutting dies so that it may be shifted to reverse itscutting angle relative to the longitudinal axis of the stripintermediate each cutting operation. However, this prior art solutionhas not been satisfactory since the use of shiftably mounted diesresults in inaccuracies in cutting the laminations.

Another problem presented when cutting transformer laminations frommaterial having special magnetic properties is that the materialrequires very delicate handling lest these properties be impaired. Whileit is possible to bend or otherwise stress the material to a certaindegree, it is imperative that such stresses be held beneath a certainvalue. In certain cases, this value may, for example, be the elasticlimit of the material; however, in other cases, this value may bematerially less than the elastic limit.

While my invention is not limited to cutting transformer laminationsfrom the strip material, it employs a novel method and apparatus whichis particularly appropriate in solving the problems heretoforementioned; and these advantages together with others will becomeapparent from a study of the following description and from the drawingsappended hereto.

In the drawings accompanying this specification and forming a part ofthis application there is shown, for purpose of illustration, anembodiment which my invention may assume, and in these drawings:

FIGURE 1 is a side elevational view of apparatus embodying my invention,

FIGURE 2 is an end elevational view of the apparatus shown in FIGURE 1,

FIGURE 3 is an elevational view corresponding to the line 3--3 of FIGURE1,

FIGURE 4 is an eleva-tional .view corresponding to the line 44 of FIGURE1,

ances of the core being assembled).

Patented Jan. 8, IE63 FIGURE 5 is an enlarged sectional view generallycorresponding to the line 55 of FIGURE 1,

FIGURE 6 is an enlarged broken fragmentary vieW generally correspondingto the line 65 of FIGURE 2,

FIGURE 7 is a still further enlarged fragmentary sectional Viewgenerally corresponding to the line 7-7 of FIGURE 6,

FIGURE 8 is a fragmentary sectional view drawn to the same scale asFIGURE 7 and generally corresponding to the line 88 of FIGURE 6,

FIGURE 9 is a fragmentary, exploded perspective view of a transformercore,

FIGURE 10 is a reduced size plan view illustrating the manner in whichtransformer laminations are cut from strip material by use of myinvention,

FIGURE 11 is a view similar to FIGURE 10 but il lustrating a prior artmanner of cutting transformer laminations from strip material,

FIGURE 12 is a fragmentary view, similar to FIG- URE 7, of anotherembodiment of the invention, and

FIGURE 13 is a diagrammatic view of a fluid circuit which may beemployed to effect the desired operation of the embodiment shown inFIGURE 12..

Referring first to FIGURE 9, wherein a conventional transformer core isfragmentarily shown, it is to be understood that the present inventionis particularly, although not necessarily, adapted to cut generallykeystone shaped transformer laminations T which are adapted to beassembled together to form a transformer core.

When building a transformer core from laminations T (see FIGURE 9), itis to be understood that laminations will be clamped together to providea rigid, unitary structure. Particularly in the larger sized cores, thelaminations will have to be forced toward the position they will occupysince it is virtually impossible to insure that each lamination will heperfectly flat and without camber. However, in assembling the core, itis of the greatest importance that the force exerted on the laminationswill be less than that which would impair their magnetic properties. Inother words, the laminations will be clamped or otherwise urged togetherwith the desirable end that the laminations will be flat and with theiredges in alignment; however, the force exerted in so urging thelaminations will be less than that which would impair their magneticproperties.

Stated another way and assuming, for the sake of illustration, that itis desirable for the laminations to be straight and flat, if they cannotbe straightened and flattened by the use of the aforesaid limited force,they will be assembled by the use of such limited force in a somewhatthan straight or flat condition (providing, of course, that in suchcondition the laminations will be sufiiciently straight and flat to meetthe dimensional toler- My invention, as will later be described, isadapted to accurately cut laminations from strip material with a minimumof scrap (see FIGURE 10) and without impairing their magneticproperties.

As seen in FIGURE 1, the apparatus therein illustrated which embodies myinvention comprises apparatus Ill which is adapted to cut thelaminations T and apparatus 11 which is adapted to feed strip material 8to apparatus it).

In the present embodiment, apparatus Iii) comprises a suitable press 12raving the usual bed 13 and the usual ram 14 (see FIGURES 2, 7 and 8).The press 12 is herein shown to be of the inclined bed type for apurpose which will later become clear and secured to the bed 13 inspaced-apart relation by any suitable means are a pair of dies 15, swhich are adapted to cut the strip material S.

As shown in FIGURE 7, die 15 comprises a lower plate 17 suitably securedto the bed 13 of the press 12 and an upper plate 18 guided for movementtoward and away from the lower plate by the usual die pins 19. Springs20 are positioned about the pins 19 and these springs yield-ably urgethe upper and lower portions of the die apart as shown. The lower plate17 of the die supports a stationary cutting blade 21 and the upper plate13 supports a movable cutting blade 22. It will readily be apparent thatas the die plates are moved together by the press ram 14, blades 21, 22will sever the strip S.

Die 16 is similar to die 15 and similar parts are therefore identifiedby the same reference numerals but with the suffix a added. However, itwill be noted that the cutting blades 21a, 22a of die 16 (see FIGURE 6)are arranged to square off a part of the end of the lamination so as toform it to the shape shown in FIGURES 9 and 10.

Means are provided for guiding the strip S intermediate the spaced-apartdies 15, 16 and as shown in FIGURE 7, such means may comprise aplate-like member 23 which extends between the lower plates 17, 17a ofthe respective dies and whose upper surface lies in the same plane asthe upper surface of the respective lower plates.

A presser plate 24 is supported in spaced relation above the plate 23and the respective upper surfaces of the lower plates 17, 17a of thedies and extends between the movable knives 22, 22a for a purpose to beshown. In the embodiment shown in FIGURES 7 and 8, plate 24 has guidepins 25 secured thereto and certain of these pins are slidable inrespective upper plates of the dies and certain other pins are slidablein brackets 26 which depend from the ram 14 of the press. Springs 27surround the pins 25 and such springs yieldably urge plate 24 towardplate 23 to clamp the strip therebetwcen when the ram 14 descends.

It will be noted that the springs 27 adjacent brackets 26 are spacedfrom the brackets in the position of parts shown in FIGURE 7. This spaceis provided so that all of the springs 27 will be compressedsubstantially simultaneously as the ram descends. Any suitable means maybe employed to maintain the presser plate 24 spaced from the lower plateof the dies and the plate-like member 23 when the dies are open. Forexample, the pins 25 which are slidable in the upper plates of the diesmay have heads 25a which seat in counterbores 25b formed in therespective upper plates of the dies.

For a purpose to be disclosed, it is desirable that the pressure exertedby plate 24 on the strip material S be adjustable; accordingly, it iscontemplated in this embodiment that the springs 27 may be replaced withstronger or weaker springs, as the case may be, when it is desired tochange the pressure. Another manner of varying the pressure might be toprovide a shim (not shown) beneath each spring, which shims could beincreased or decreased in thickness by adding or removing shim membersas required.

Means are also provided for locating the edge of the strip Stransversely of the dies 15, 16 and such means are presently shown tocomprise a plurality of locating pins 28 positioned, in the embodimentdisclosed, in a straight line along one side of the strip (see FIGURES 6and 8). At the present time, three locating pins are employed, oneadjacent each pair of cutting knives and one intermediate the dies. Aswill be understood, pins 23 are shiftable from the extended positionshown in FIG- URE 8 wherein they are engageable with the strip S to aretracted position wherein they are clear of the strip and such shiftingmovement may be accomplished by any suitable means such as by means offluid cylinders 29.

As also seen in FIGURES 6 and 8, means are provided for urgin the stripmaterial toward engagement with each of the locating pins 28 and suchmeans may comprise plungers 32) which are presently shiftable toward andaway from the strip by means of fluid cylinders 31. As best shown inFIGURE 6, each plunger 30 is preferably in opposed relation with arespective pin 28 and each is movable by its respective cylinder to urgethe strip material toward engagement with locating pins 28 to therebyapply a force edgewise of the strip tending to straighten it in theevent it is cambered.

Cylinders 31 are preferably air actuated and are connected to a sourceof air pressure by means of a suitable valve (not shown) which controlsflow of air thereto and therefrom. A pressure regulator valve (seeFIGURE 6) is interposed in the line between cylinders 31 and the sourceor" air pressure to provide for adjustment of the pressure exerted bysuch cylinders for a purpose to be disclosed.

Operation of apparatus 10 thus far disclosed will now be described.Assuming that the respective upper and lower plates of the dies 15, 16are separated as shown in FIGURES 7 and 8 and that the pins 28 areextended and plungers 30 retracted .as shown in FIGURE 8, a piece ofstrip 5 will be fed between the dies by means later to be disclosed.

The strip will be guided longitudinally on .one edge by means of thepins 28 and on the other edge by means of a shoulder 32 which extendsupwardly from and forms a part of guide plate 23.

After the strip has been positione d between the dies, cylinders 31 willbe actuated to move plungers 39 into engagement with the edge of theadjacent strip portion. This will crowd the edge of the strip portiontoward engagement with each of locating pins 28, thus tending to remove,in the present case, any camber (or curvature) which may exist in suchedge portion. It is to be understood that the regulator Valve in theline feeding cylinders 31 will be so adjusted that the force exerted bythe cylinders on the strip portion will not exceed the force which willbe exerted on the finished lamination at its assembly into thetransformer core. By thus limiting the force exerted by the cylinders,the strip will not be stressed an amount whereinits magnetic propertieswould be impaired.

The press 12 will now be actuated to move ram 14 toward the bed of thepress. As the ram 14 engages the respective upper plates of the dies 15,16 and moves them downwardly toward their respective lower plates,presser plate 24 will first engage the adjoining side of the stripportion and firmly clamp such portion against the upper surfaces of thelower Plates of the dies 15, 16 and the upper surface of the plate 23.This will tend to straighten out the strip and insure accurate cuttingthereof. It should be pointed out that springs 27 will be so chosen (ortheir effectiveness adjusted by means of shims or the like as beforementioned) that the flattening force exerted on the strip by pressureplate 24 will not exceed that which will be applied to the finishedlamination at asembly into the transformer core to insure against animpairment of the laminations magnetic properties.

Continued movement of the ram 14 will cause each die to sever itsrespective end of the strip portion substantially simultaneously, andretraction of the ram will permit the dies to once again spring open.Pins 28 will then be retracted by cylinders 29 and this will permit thesevered portion of strip (now out to form a lamination T) to fall fromthe dies since the press is of the inclined type. The pins 28 will thenbe extended by cylinders 29, the plungers 30 retracted by cylinders 31and the strip fed between the dies once again.

In the embodiment shown in FIGURE 12 wherein similar parts areidentified with the same reference characters but with the suffix 1)added, springs 27 and pins 25 have been replaced by fluid cylinders 161carried by the respective upper die plates and the brackets which dependfrom the press ram. Cylinders 101 are preferably air actuated in amanner to be disclosed and each has a piston rod 102 whose free end issecured to the pressure plate 24b.

A constant air pressure is adapted to be maintained on cylinders 101 toresiliently maintain pressure plate 241) in the position illustrated andas seen in FIGURE 13, cylinders 101 are Connected to a source of airpressure via an air storage tank 103, a check valve 164 and a constantpressure regulator valve 105. Valve 105 will be so adjusted that theforce exerted by cylinders 101, which force is in turn transmitted tothe strip by means of pressure plate 24b when the press ram descends,will not exceed the force which will be exerted on the finishedlamination at its assembly into the transformer core to thus insureagainst an impairment of the laminations magnetic properties.

As the press ram descends, pressure plate 24b will tend to flatten thestrip until such flattening force exceeds the pressure exerted bycylinders 101. When this point is reached, piston rods 102 will beforced upwardly in their cylinders, against the air pressure within thecylinders, to absorb the overtravel of the press ram. The pressureexerted by cylinders 101 will be substantially constant and will notmaterially increase as the piston rods are forced upwardly since therelatively large storage tank 1493 will absorb the air displaced fromthe cylinders. Check valve 104, of course, will prevent flow of air in areverse direction to the regulator valve Hi5.

Normally, if the strip were fed to the apparatus in the conventionalmanner, considerable waste strip would result (see portions W in FIGURE11). However, the present invention reduces to a minimum the amount ofscrap formed by turning the strip side for side about its longitudinalaxis, intermediate each cutting operation.

Referring once again to FIGURE 1 wherein apparatus 11 for feeding thestrip to the press 12 and for turning the strip in the manner mentionedis illustrated, it will be seen that such apparatus comprises abarrel-like structure 33 which is rotatably supported by flanged rollers34 which are rotatably carried by respective roller supports 35.

As shown in FIGURES 1 and 4, strip feeding means 36 is suitablysupported within the structure 33 and such means is preferably, althoughnot necessarily, of the type disclosed in my co-pending application forLetters Patent, Serial Number 374,903, now US. Patent No. 2,819,070,issued Jan. 7, 1958, and U.S. Reissue No. 24,883, issued Get. 11, 1960,entitled Mechanical Movement Particularly for Feed Apparatus. Suchfeeding means comprises juXtaposed rolls 37, 37 which provide a pass forthe strip material and which are adapted to be rotated by means such asdisclosed in the aforementioned copending application to feed apredetermined length of strip through the pass. It should be sufficientto disclose thta the rolls 37, 37 grip the strip tightly and are adaptedto be rotated a predetermined amount and thereafter stopped so as tofirmly hod the strip in position. It is to be understood, however, thatthe particular feeding means shown is disclosed for purpose ofillustration only and that any other suitable feeding means may beemployed.

The strip S is adapted to be guided through the center, or axis ofrotation, of the structure 33 to the feeding means 36 by means of rollscarried by spaced-apart roll stands 38 and 39. As best seen in FIGURE 3,rolls 4'1 43 provide a pass for the strip and are rotatably supported bythe roll stand 38 in any suitable manner.

In order to prevent excessive twisting of the strip, the rolls 4t 49 areso positioned that the pass provided thereby holds the strip in aposition which is normal to the position of the strip when it is alignedwith the dies of the press 12 (compare FIGURES 2 and 3). In this manner,although the strip is turned from side to side about its longitudinalaxis through an angle of 180 degrees by means to be disclosed, the stripwill be twisted through an angle of only 90 degrees in either directionwith re- 6 spect to the position in which it is supported by the rolls40, 40.

Furthermore, since the present invention is adapted for use with stripwhich requires particularly gentle handling the amount that the strip istwisted, the width of the strip and the length of strip through whichsuch twisting occurs preferably is so proportioned that the stresses setup in the strip by such twisting will be less than that which wouldimpair the magnetic properties of the strip.

Roll stand 39 is similar to roll stand 38 in that it rotatably supportsa pair of rolls which provide a pass for the strip. However, in thepresent embodiment, the axes of the rolls carried by roll stand 39 andthe pass provided by the rolls are horizontal.

As shown in FIGURES 1, 4 and 5, roller supports 35 are secured to aslide 41 which is slidable in a guideway 42 supported by the floor orother supporting surface. For a purpose to be disclosed, means areprovided for shifting the slide and its supported structure 33longitudinally of the axis of the strip and such means presentlycomprises a fluid cylinder 43 (see FIGURE 1) secured to the slide 41 andhaving a piston rod 44 which is anchored to the floor or othersupporting surface by means of a suitable bracket 45. Reciprocation ofcylinder 43 rela tive to the piston contained therein will efiectreciprocation of the slide 41, structure 33 and the feeding mechanism 36carried thereby.

Means are provided for effecting rotation of structure 33 about its axisand the coinciding longitudinal axis of the strip and such meanscomprise a sprocket 46 supported at one end of the structure by suitablesupports 47. A chain 48 has an intermediate portion trained oversprocket 46 and end portions trained over respective sprockets 49 whichare supported by respective brackets 50 secured to slide 41 (see FIGURE5). Each end portion of chain 48 is also trained over respectivesprockets 51 each of which is rotatably secured to a respective end of apiston rod 52 which extends from opposite ends of a fluid cylinder 53.Fluid cylinder 53 is secured to the slide 41 by any suitable means andeach extreme end of chain 48 is anchored to a respective adjoiningbracket 50 by any suitable means.

When piston rod 52 is shifted to the right as viewed in FIGURE 5, chain43 will effect rotation of structure 33 in the direction of the arrow.Since sprocket: 46 is in the form of a ring, strip may be passed throughthe center thereof without interfering with rotation of the sprocket.

Operation of the present invention is as follows: Strip S will be fedbetween the rolls carried by roll stand 39, then between the rolls 40,46 carried by roll stand 38, through the center of sprocket 46 and tothe feeding means 35. The feeding means will then be actuated by anysuitable means to feed a predetermined length of strip to the open dies15, 16 of the press 12 and operation of the press will thereupon beinitiated to sever the strip as heretofore described.

After the press has completed its cycle and a piece has been severedfrom the strip, the severed piece will fall from the dies as previouslydescribed and cylinder 43 will be actuated to shift structure 33 in adirection away from the press from the full line position shown inFIGURE 1 to the dot-dash line position. It is to be understood that suchmovement of structure 33 will withdraw the end of the strip from the die15 for a purpose to become clear since the strip is tightly gripped bythe rolls 37, 37 of the feeding means 36.

After cylinder 43 has shifted structure 33, any suitable means may beemployed to effect operation of cylinder 53 to rotate structure 33 anamount sufficient to turn the strip side for side about its longitudinalaxis. Since the strip has been withdrawn from the die 15, it may befreely turned. After the strip has been turned, cylinder 43 will returnstructure 33 to its full line position and feeding means 36 will operateto feed another predetermined length of strip to the press.

It is to be understood that the amount of material fed at each operationof the feeding means is suflicient to extend only a slight amount beyondthe cutting knives 21a, 22a of die 16 to minimize scrap. By way ofexample, suflicient strip may be fed at each operation of the feedingmeans to extend approximately one-eighth of an inch beyond the knives ofdie 16. This is indicated in FIGURE 10.

It will now be clear that turning the strip side for side intermediateeach cutting operation permits the cut made by die 16 to be positionedclose to and parallel with the cut made by die 15 at the preceding pressoperation to thereby minimize scrap.

While it is preferable in the presently disclosed embodiment to employtwo dies for cutting the strip material in order to insure cuttingaccuracy, it will be understood that under certain circumstances it maybe desirable to employ only one die. In such event, turning the stripside for side intermediate each cutting operation will reverse therelationship of the cut end of the material and the cutting die and willpermit generally keystone shaped pieces to be cut with a single die.

In view of the foregoing it will be apparent to those skilled in the artthat I have accomplished at least the principal object of my inventionand it will also be apparent to those skilled in the art that theembodiments herein described may be variously changed and modified,without departing from the spirit of the invention, and that theinvention is capable of uses and has advantages not herein specificallydescribed, hence it will be appreciated that the herein disclosedembodiments are illustrative only, and that my invention is not limitedthereto.

1 claim:

Apparatus for cutting sheet-like material comprising a pair ofspaced-apart cutters for cutting material in operable relationtherewith, clamping means intermediate said cutters and having spacedportions engageable with respective opposed side edges of the materialfor clamping the latter position prior to cutting thereof with one ofsaid material side edges disposed at a lower level than its oppositeside edge, and means for moving that clamping means portion engaged withsaid one material side edge in a direction flatwise of the material andaway from engagement with the latter following cutting thereof toprovide for gravitation of the cut material away fro-m said cutters.

References Cited in the file of this patent UNITED STATES PATENTS1,381,110 Dyblie June '14, 1921 1,982,880 Pachter Dec. 4, 1934 2,017,752Fisher Oct. 15, 1935 2,165,614 Cook et a1 July 11, 1939 2,699,209 NortonJan. 11, 1955 2,766,825 Pater et a1. Oct. 16, 1956 2,815,074 Dehn Dec.3. 1957 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent N003,072,001 January 8, 1963 Richard F, Herr It is hereby certified thaterror appears in the above numbered patent requiring correction and thatthe said Letters Patent should read as corrected below.

column 2, line 61, for "material 8" read material S column 8, line 11,after "latter" insert in Signed and sealed this 6th day of August 1963.,

(SEAL) Attest:

ERNEST w. SWIDER DAVID LADU Attesting Officer Commissioner of Patents

